1. Field of the Invention
The present invention relates to a fixing device using a clamp for attaching an elongated member to a basic structure and more particularly to an improvement in a mechanism of engaging and fixing the elongated member to the basic structure. The elongated member may be a metallic tube, resin tube, wire harness, rod or cable having a comparatively small diameter of less than about 20 m/m and generally serving as an oil or air supply passage of an automobile, or as one of constitutional elements of various kinds of machines and equipment.
2. Description of Prior Art
One example of the conventional fixing device of the above type is such that as shown in FIG. 13, where an elongated member such as a small-sized tube P' is attached to a basic structure, the outer periphery of the P' is fastened to a clamp 11 having a fitting hole 13 at one end, a flat fitting wall 12 and a hook wall 14 which is coiled larger than a semicircle at the lower end of the flat fitting wall 12, in such a manner that the entire outer periphery of the tube P' is fastened to the inner surface of the hook wall and the free end or the entire inner surface of the hook wall and the outer periphery of the tube P' contacting the former are brazed by heating as at 15.
Another example, as shown in FIG. 14, is such that the outer peripheries of elongated members of different diameters such as a large-sized tube P" and a small-sized tube P' are fastened to the entire inner surfaces of a couple of fastening walls 16 and 16' each coiled larger than a semicircle at both ends of a bandlike clamp 11 and the contact surfaces of the tubes and the fastening walls are brazed tightly by heating as at 14 and 14' respectively.
However, the former device has had the disadvantage that it provides a fixing mechanism by engagement of the outer periphery of the small-sized tube P' with the entire inner surface of the coiled hook wall 14 of the clamp 11 and since the distance between the fitting wall 13 and the hook wall 14 of the clamp 11 is short, when the tube P' is laid in position, external impact applied on the tube P' and the vibrations thereof transmitted to the tube from the basic structure are not absorbed and damped. Further, the latter device has also had such disadvantages that it provides a fixing mechanism by the engagement of the outer peripheries of the large-and small-sized tube P" and P' with the entire inner surfaces of the fastening walls 16 and 16', respectively, formed at both ends of the clamp 11 and therefore, when the tubes are laid in position, impact on the large-sized tube P" and vibrations thereof transmitted to the small-sized tube P' are not absorbed and damped so that the tubes, especially the small-sized one, is liable to get deformed or fatigued or produce noises and when the tube is made of an extremely thin material, the mechanical strength of the tube deteriorates due to the tube being heated locally by the manual brazing operation which results in a cracking or damage of the portion adjacent the fastening portion of the clamp member 11. Further, as the larger and small-sized tubes P" and P' are fastened to the fastening walls 16 and 16' coiled more than semicircles of diameters substantially equal to those of the tubes, a trouble is incurred in moving the tubes in the longitudinal direction through the coiled fastening walls and moreover, should the tubes include bent portions, the passage of these bent portions through the fastening walls are often hindered. In addition, due to the difference of bending accuracy between the tubes P" and P' or the difference of the fixing position or angle of the clamp 11, when the tubes are laid in position, the tubes and the clamp 11 are sometimes deformed or applied with residual stress because of an unreasonable way of fixing them and the structure fails to meet the expansion and contraction of the tubes due to a temperature change resulting in generating a thermal stress.